Answer:
It's producers because those are the one's that sell them to the consumers.
Cold air usually pushes warm air because cold air has a HIGHER DENSITY
Plants and animals live in interacting, interwined communities. There is a characteristic set of species in different environments. For example, certain species of trees, shrubs, ground cover, arthropods, reptiles, mammals, birds etc. live in a temperate forest environment. A completely different set of creatures live in a marsh, or a grassland or an agroecosystem. However, the relationships between these groups can be defined by the ecological role they play, the flow of energy between them and the cycling of nutrients between them. This is a fancy way of saying "everything is connected"! And if you change one part of the system, something else changes. In an ecosystem management decision, you hope you know what those consequences of your actions are!) This is important in managing agroecosystems as well.
